Acidithrix ferrooxidans (A. ferrooxidans) is a heterotrophic, acidophilic and Gram-positive bacterium from the genus Acidithrix. The type strain of this species, A. ferrooxidans Py-F3, was isolated from an acidic stream draining from a copper mine in Wales.[1][3][4] This species grows in a variety of acidic environments such as streams, mines or geothermal sites.[1] Mine lakes with a redoxcline support growth with ferrous iron as the electron donor.[1][5] "A. ferrooxidans" grows rapidly in macroscopic streamer, producing greater cell densities than other streamer-forming microbes.[6] Use in a bioreactors to remediate mine waste has been proposed due to cell densities and rapid oxidation of ferrous iron oxidation in acidic mine drainage.[6] Exopolysaccharide production during metal substrate metabolism, such as iron oxidation helps to prevent cell encrustation by minerals.[5]
| Acidithrix ferrooxidans | |
|---|---|
Scientific classification 
| |
| Domain: | Bacteria |
| Phylum: | Actinomycetota |
| Class: | Acidimicrobiia |
| Order: | Acidimicrobiales |
| Family: | incertae sedis |
| Genus: | "Acidithrix" Kay et al. 2013[1] |
| Species: | A. ferrooxidans
|
| Binomial name | |
| Acidithrix ferrooxidans Kay et al. 2013[1]
| |
| Type strain | |
| DSM 28176 JCM 19728 Py-F3[2] | |
Isolates/Sequencing
editIsolate Py-F3
editType strain Py-F3 was isolated from acidic, metal-rich mine waters in North Wales.[5] Py-3 can grow different metabolisms for potential growth substrates,[4] and can grow at a range of temperatures from 10 to 30 °C and pH from1.5–4.4.[4] Strain Py-F3 encodes multiple enzymes for carbon fixation, including RubisCO, but its carbon fixation activity has not been studied.[4] Genes encoding proteins for metabolic pathways utilizing sulfur, nitrogen, and iron were discovered in the genome.[4] The source of sulfur is sulfate, and it can use amino acids as a nitrogen source. This is unique requirement of isolate Py-F3, leaving it with an inability to grow in media unless complex substrates are added.[4] For pH homeostasis the urease genes could aid survival due to encoded the proton pumping activity.[4] Uptake of urea is documented in Py-F3 and allows for the intracellular production of urea, rather than taking it in to the cell.[4] This organism's peptidoglycan contains meso-diaminopimelic acid and with major fatty acid chains and a respiratory quinone.[4]
Isolate C25
editIsolate C25 was recovered from particulate iron forming in a pelagic iron-rich redoxcline zone of a mine lake.[5] This isolate can both oxidize Fe(II) and reduce Fe(III) under micro-oxic conditions, and was suggested to contribute to the formation of particulate iron in the pelagic environment.[5] Growth did not occur at pH lower than that of Py-F3 (pH) of 2, while C25 had a higher pH tolerance.[5] The observation that C25 can both oxidize and reduce iron provides insights into how microbes cycle both iron and organic carbon under acidic conditions.[5] Fast rates of iron oxidation lead to the regeneration of ferric iron in the environment at a pH as low as 1.5.[7][6] Compared to Py-F3, C25 did not encode for the ribulose, but future studies will need to be done for a definitive answer.[5]
Application to Bioremediation
editThe strains grow using iron metabolism on Tryptic Soy Broth/Agar (TSA/TSB) at low pH, where bacterial colonies form with iron precipitates.[5][6] Lab conditions of 25 °C aerobically allowed for ferrous iron oxidation to occur in sterilized lake medium.[5] Researchers recognized the potential of utilizing "A. ferrooxidans" for a bioreactor through growth/adherence on solid surfaces.[6] Iron mines make an excellent growing condition and analogy for the bioreactor due to those similar surfaces.[6] Utilizing the bacteria can facilitate soluble iron removal from ferruginous water, and the iron (III) production contributes to sulfide minerals dissolving.[6]
References
edit- ^ a b c d e Jones, RM; Johnson, DB (2014). "Acidithrix ferrooxidans gen. nov., sp. nov.; a filamentous and obligately heterotrophic, acidophilic member of the Actinobacteria that catalyzes dissimilatory oxido-reduction of iron". Research in Microbiology. 166 (2): 111–20. doi:10.1016/j.resmic.2015.01.003. PMID 25638020.
- ^ Euzéby JP, Parte AC. "Acidithrix ferrooxidans". List of Prokaryotic names with Standing in Nomenclature (LPSN). Retrieved May 10, 2022.
- ^ Parker, Charles Thomas; Garrity, George M (2015). Parker, Charles Thomas; Garrity, George M (eds.). "Nomenclature Abstract for Acidithrix ferrooxidans Jones and Johnson 2015". The NamesforLife Abstracts. doi:10.1601/nm.27541 (inactive 1 November 2024).
{{cite journal}}: CS1 maint: DOI inactive as of November 2024 (link) - ^ a b c d e f g h i Eisen, Sebastian; Poehlein, Anja; Johnson, D. Barrie; Daniel, Rolf; Schlömann, Michael; Mühling, Martin (30 April 2015). "Genome Sequence of the Acidophilic Ferrous Iron-Oxidizing Isolate Acidithrix ferrooxidans Strain Py-F3, the Proposed Type Strain of the Novel Actinobacterial Genus Acidithrix". Genome Announcements. 3 (2): e00382-15. doi:10.1128/genomeA.00382-15. PMC 4417699. PMID 25931603.
- ^ a b c d e f g h i j Jiro F. Mori; Shipeng Lu; Matthias Händel; Kai Uwe Totsche; Thomas R. Neu; Vasile Vlad Iancu; Nicolae Tarcea; Jürgen Popp; Kirsten Küsel (2016-01-01). "Schwertmannite formation at cell junctions by a new filament-forming Fe(II)-oxidizing isolate affiliated with the novel genus Acidithrix". Microbiology. 162 (1): 62–71. doi:10.1099/mic.0.000205. ISSN 1350-0872. PMID 26506965.
- ^ a b c d e f g Jones, Rose M.; Johnson, D. Barrie (2016-07-15). "Iron Kinetics and Evolution of Microbial Populations in Low-pH, Ferrous Iron-Oxidizing Bioreactors". Environmental Science & Technology. 50 (15): 8239–8245. Bibcode:2016EnST...50.8239J. doi:10.1021/acs.est.6b02141. ISSN 0013-936X. PMID 27377871.
- ^ Hu, Danyu; Cha, Guihong; Gao, Beile (2018). "A Phylogenomic and Molecular Markers Based Analysis of the Class Acidimicrobiia". Frontiers in Microbiology. 9: 987. doi:10.3389/fmicb.2018.00987. ISSN 1664-302X. PMC 5962788. PMID 29867887.
